iclight,
Different mechanism of action. Direct causes pseudoprogression and then cell death that leads to necrosis. What was left behind in some cases was a completely dead tumor which was then surgically removed. Pseudoprogression caused treatment to be stopped leading to incomplete immune response in many as well. Two versions, three different dose levels, deliberate improper spacing of treatments and only one tumor injected kept this “first in man” approach from being throughly effective as well.
What was learned has created an improved Direct treatment regimen that is extremely effective but would have faced many of the same product release hurdles that L has faced but now is ready to rock and roll as soon as L is approved and the next steps are financially feasible. Your work here is almost done; ). Best wishes.